The invention relates to a thermostatic mixing valve for mixing two flows and more particularly in the sanitary field for mixing hot water and cold water. The invention relates more precisely to the adaptation of automatic thermostatic regulation to a valve of a particular type, where the regulation of the flows is achieved by the relative movement of two plates, generally made from ceramics, by means of a single pivoting lever for regulating both the total flow of the mixture and its temperature. By automatic thermostatic regulation is meant the automatic adjustment of the temperature of the mixture to a predetermined value for the median position of the pivoting lever.
Mixing valves with ceramic (sintered aluminium oxide) plates are known, also called "mirrors" because of their smooth surfaces by which they are in mutual contact. The plates comprise passages and/or characteristics of form for regulating both the rate and the mixture of the two flows. In the field of sanitary taps and fittings, these devices are more and more widely used for mixing hot water and cold water. By way of example, the French patent application No. 2,592,127 describes such a ceramic plate mixing valve controlled by a single pivoting lever of the ball lever type and having as main advantage a real independence of the two types of regulation. In other words, the temperature of the mixture is not modified when the lever is actuated vertically for adjusting the flowrate, and conversely, this flowrate does not vary when the temperature of the mixture is changed by moving the same lever horizontally. However, the temperature corresponding to the median position of the lever depends essentially on the respective temperatures and pressures of the hot water and cold water sources. Depending on the case, the range of use of the regulating lever may then be offset towards one end of the travel of the control lever and make the temperature regulation more difficult.
Conventional sanitary plumbing installations are further known, i.e. having separate regulation means for the hot water and the cold water, incorporating a thermostatic element, known per se, and adapted for providing automatic regulation of the mean temperature of the mixture. This mean temperature is thus predetermined and regulated through the thermostatic regulation element. Such a thermostatic regulation element is for example formed of a metal capsule with telescopic structure, filled with wax capable of expanding, expanding of the wax results in a variable elongation of the capsule in a predetermined longitudinal direction. An installation of this kind is described for example in the French Pat. No. 2,250,934.
The invention consists in combining a thermostatic regulation arrangement incorporating such a regulation element with a smooth plate mixing valve, particularly with ceramic plates, of the above described kind.